Foldable antenna



'ay 12, 1942, M. Z EH FOLDABLE ANTENNA Filed Aug. 5, 1939 INVENTOR.

ATTORNEY.

Patented May 12, 1942 FOLDABLE ANTENNA Martin Zeh, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphic, m. b. H., Berlin, Germany, a corporation of Germany Application August 5, 1939, Serial No. 288,514 In Germany August 11, 1938 Claims.

For portable small radio apparatus, antennas are required which are to have a certain rigidity while in use since they are not suspended but are generally fastened to the apparatus, for instance, as self-supporting rod antennas. For transporting such antennas they should be adapted such so that they can be folded up, then they will require only a small space to facilitate packing. In the prior art, tubings or the like have been employed which could be concealed within one another in the manner of a telescope but these tubings have disadvantages as they are not Very resistible against impact and rough treatment which limit their use for portable apparatus.

This invention provides an antenna which is free from the above-mentioned disadvantages and which, also, has the advantage of a certain flexibility when placed in the operative state, so that there exists a cetrain yield when the antenna is subjected to considerable stress caused by impact or the like which prevents buckling, a condition which exists in the hitherto known rod antennas.

In accordance with the present invention, a foldable antenna is constructed from two elastic metal bands which are arranged parallel to one another whereby the planes of these bands extend at right angle to one another when the antenna is in operation, while they are parallel to one another when the antenna is folded up. Preferably the two metal bands are connected by means of hinges and an arresting device is provided by means of which the two metal bands are held in the desired relative position.

The invention will now be elucidated in reference to the accompanying figures, in which:

Fig. 1 is a longitudinal section partly in perspective of the antenna in the operative position;

Fig. 1A is a plan view of the plug pin bushing arrangement on the portable apparatus;

Fig. 2 is a plan view of Fig. 1;

Fig. 3 is a modification of Fig. 2;

Fig. 4 is a longitudinal side view of the antenna in a non-operative position;

Fig. 4a. is a partial front view of Fig. 4;

Fig. 5 is a plan view of Fig. 4;

Fig. 6 is a longitudinal section of another modification;

Fig. 6A is a detail of the guide member for Fig. 6;

Fig. 6B is a detail of a block member for Fig. 6.

Fig. 1 shows an example of construction embodying the idea of the invention and in which the two elastic metal bands I, 2 consisting, for instance, of steel are connected together at one end by means of a hinge 3. The one steel band is provided with a plug pin 5 at its lower end and by means of said pin the antenna can be inserted into the bushing B of the small transmitter or small receiver for which it is to be used. The other steel band has an arresting pin 1 which fits into a corresponding bushing 8 in the apparatus. The two bushings 6 and 8 are arranged at a distance such that when inserting the plug pins 5 and 1 into the bushings the two steel bands form a right angle with one another as shown in Fig. 2, thus providing a rigid structure. The entire antenna is concealed in a hose of elastic insulating material such as, for instance, in a rubber hose 9 having a sufficient width.

Fig. 3 shows a modification of the invention whereby the center of the hinge is in the center of the two steel bands such that the two steel bands form a T when in the operative state.

Fig. 4 shows the antenna packed-up whereby the structure is no longer rigid and the hinge 3 may then be folded up which brings the two steel bands I and 2 in a parallel position as can be seen in the cross section Fig. 5. The antenna can, in this state, be easily wound into a roll and requires but little space when put together in this way. Fig. 4a shows a front view of Fig. 4.

In placing the antenna into a rubber hose, the two steel bands are given a certain yieldableness so that in case of a strong buckling force the steel bands can yield at the deformation of the rubber hose whereby the antenna can buckle without being thereby destroyed. As soon as the buckling force recedes, the antenna springs back into its original position. The invention is not limited to the example of construction shown and can be employed wherever a conductor piece is to be used as desired in a rigid state in which it has a relatively high resistibility against buckling, or in the flexible state.

A further example of construction embodying the idea of the invention is shown in Fig. 6, in which no hinges are employed but the two steel bands I and 2 which form a right angle with one another are fixedly secured to a block 33 provided with the plug pin 5. The guide piece 4 supports the two steel bands at the upper end thereof in the position at right angles to one another. This guide piece is fixedly connected with the one steel band I, for instance by way of soldering, or riveting, while the other steel band can slide in slots so that it can yield when the antenna is rolled up. Also, this mode of construction permits of a folding up into a small unit of the steel bands positioned at right angles to each other, and this in view of the yieldableness. At the folding up stage, the two steel bands will lie parallel to one another.

What is claimed is:

1. A foldable antenna comprising a first and a second metal band normally arranged parallel to each other in the folded state, a block fastened to the lower end of both said first and second bands to retain them in a position at right angles to each other, and a guide member located at the upper end of said first band and having a slot in which said second hand may move.

2. A foldable antenna comprising two metallic bands normally arranged parallel relative to each other in the folded stage, an electric terminal member secured to at least one of said bands, and means for so disposing said bands that the planes of said bands extend at right angles relative to each other when said antenna is in the operative state, and an elastic insulating hose surrounding said bands.

3. A foldable antenna comprising a first and a second metal band normally arranged parallel to each other in the folded state, a block fastened to the lower end of both said first and second bands to retain them in a position at right angle to each other, a guide member located at the upper end of said first band and having a slot in which said second band may move, and an electrical terminal member fastened to said block.

4. An antenna comprising a pair of elongated elastic conductive bands arranged in separate planes, the elements of said planes being parallel in the direction of the length of said bands, means for supporting said bands in a position one relative to the other such that said planes intersect at right angles and means for moving said bands into parallelism for at least a portion of their length whereby said antenna may be folded in said portion.

5. An antenna comprising a pair of elongated elastic conductive bands arranged in separate planes, the elements of said planes being parallel in the direction of said bands, means for supporting said bands in a position one relative to the other such that said planes intersect at right angles, said bands being adapted to be moved into parallelism for at least a portion of their length whereby said intenna may be folded in said portion.

MARTIN ZEH. 

